AI Agent for Candidate Sourcing

Source Candidates. Automatically.

Use StackOne to connect your AI agent to your ATS, talent CRM, and outreach tools to automate candidate sourcing and outreach.

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AI Agents

Connect

MCP and A2A to REST, SOAP, and proprietary APIs.

Optimize

Tool discovery, data shaping, and reliable execution.

Secure

Scoped permissions, audit trails, and observability.

StackOne Integration Layer

list_jobs

greenhouse

search_candidates

hubspot

get_candidate

greenhouse

send_email

gmail

update_application

greenhouse

send_message

slack

Your AI Agent

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StackOne Integration Layer

Connect

450+ connectors, build your own, and multi-protocol support.

All Connectors →AI Connector Builder →MCP →

Optimize

Context, token, and speed optimization infrastructure.

Falcon execution engine →

Secure

Permissions API and prompt injection protection.

Agent governance and safety →

What Can AI Agents Do for Candidate Sourcing & Outreach?

An AI agent for candidate sourcing and outreach connects to your ATS apps through StackOne to intake roles, pull candidate context, send personalized outreach, and track responses.

01

Receive Sourcing Request

Capture new role requirements from Greenhouse, Lever, or Ashby. Extract job title, required skills, location, and seniority level.

02

Search Talent Pools

Query internal talent CRM in HubSpot or Salesforce using structured search parameters to surface passive candidates matching the role criteria.

03

Deduplicate and Rank

Cross-reference results across sources, remove duplicates, and score candidates on skill match, recency, and location fit. No keyword rules — the agent reads and understands.

04

Enrich Candidate Profiles

Pull additional context from CRM records — current company, past roles, recruiter notes — to personalize outreach and prioritize the strongest matches.

05

Execute Personalized Outreach

Generate and send tailored messages via Gmail or sales engagement tools, respecting daily send limits and channel preferences for each candidate.

06

Track Responses and Update ATS

Monitor replies and engagement via connected messaging integrations. Move responding candidates into the Lever or Greenhouse pipeline and notify the recruiter.

01

Receive Sourcing Request

Capture new role requirements from Greenhouse, Lever, or Ashby. Extract job title, required skills, location, and seniority level.

02

Search Talent Pools

Query internal talent CRM in HubSpot or Salesforce using structured search parameters to surface passive candidates matching the role criteria.

03

Deduplicate and Rank

Cross-reference results across sources, remove duplicates, and score candidates on skill match, recency, and location fit. No keyword rules — the agent reads and understands.

04

Enrich Candidate Profiles

Pull additional context from CRM records — current company, past roles, recruiter notes — to personalize outreach and prioritize the strongest matches.

05

Execute Personalized Outreach

Generate and send tailored messages via Gmail or sales engagement tools, respecting daily send limits and channel preferences for each candidate.

06

Track Responses and Update ATS

Monitor replies and engagement via connected messaging integrations. Move responding candidates into the Lever or Greenhouse pipeline and notify the recruiter.

Why Building a Good Sourcing AI Agent Is Hard

Building a good sourcing agent is hard because it has to connect to more than fifteen ATS and recruiting providers, keep token costs down as candidate volume grows, defend against prompt injection in resume text, and rely on purpose-built tools to reach high accuracy.

Connecting to 15+ ATS and Recruiting Providers

A sourcing agent needs to search candidates in Greenhouse, Lever, or Ashby, pull contact data from a talent CRM, and log outreach back to the ATS. Building and maintaining connectors for each — API keys vs OAuth vs bearer tokens, provider-specific candidate schemas — is a massive lift.

Token Cost Grows with Candidate Volume

Without search-first architecture, the agent pre-loads every ATS and CRM action definition before evaluating a single profile. At scale — sourcing across thousands of candidates per req — token costs compound with every provider the agent touches.

Resume Text Carries Prompt Injection Risk

Sourcing agents ingest candidate profiles, cover letters, and notes from untrusted sources. A single adversarial instruction in a resume summary field can hijack the agent into skipping qualified candidates or exfiltrating profile data.

Getting High Accuracy Requires Purpose-Built Tools

Effective sourcing requires searching by skills, seniority, and location, then writing structured outreach records back to the ATS. Raw API wrappers expose too many low-level details and lead to hallucinated candidate field mappings.

How StackOne Makes Sourcing AI Agents Possible

StackOne makes candidate sourcing and outreach agents possible by connecting them to your ATS apps, so one agent can search talent pools, send personalized outreach, and track responses with the controls IT demands.

450+ connectors with 27,000+ agent-optimized actions

Pre-built connectors for Greenhouse, Lever, Ashby, Bullhorn, HubSpot, Salesforce, and Gmail with full native action coverage and agent instructions included.

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Managed Auth handles credentials across providers

OAuth flows, API keys, and token refresh managed per tenant for every connected ATS and CRM — no custom auth code per recruiting platform.

Agent Auth →

Search and execute finds the right action

Agent searches StackOne's catalog by natural language and executes the matching ATS or CRM action — no pre-loading thousands of tool definitions. Saves tokens at high-volume sourcing.

Tools Discovery →

Build agentic workflows

Subscribe your AI agents to any webhook-enabled ATS connector and trigger agentic workflows from any of your app events.

Webhooks for AI agents →

AI Connector Builder extends to any recruiting platform

Build custom connectors for unsupported ATS tools via REST API configuration with AI-assisted tooling and YAML definitions — no waiting on vendor roadmaps.

Connector Builder →

Defender blocks prompt injection from candidate data

StackOne Defender screens candidate profile data and resume content for injection attempts before it reaches the agent, preventing manipulation from untrusted text fields.

Prompt Injection Defense →

You Control What the Agent Can Do

Scoped permissions define exactly which candidate fields the agent reads and what actions it takes. Full audit trail of every sourcing operation.

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Integrates with your entire recruiting stack. Whatever it is.

Create Recruiting Actions & Connectors →

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Automate Candidate Sourcing with any AI agent through StackOne

Any AI Agent Client or Framework

Claude, OpenAI, LangChain, Vercel AI SDK, CrewAI, Pydantic AI — StackOne works with every major agent framework out of the box.

Any Agent Builder

Whether you're building with code, a visual builder, or an enterprise platform — StackOne provides the integration layer your agent needs.

MCP REST API A2A

Any Protocol

Pick the protocol that fits your stack. Tool calling, direct API integration, agent-to-agent messaging, or structured action workflows — all supported out of the box.

Connect Your Agent to Your Recruiting Stack

Start building in minutes. MCP connectors to every system your agent needs.

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Frequently Asked Questions

You need connectors to every ATS, CRM, and outreach tool your customers use, plus logic for profile matching, personalized messaging, and interaction logging. The hardest part is integrating across providers that each handle authentication, pagination, and rate limits differently — multiplied by every new customer's tool stack.

Three challenges dominate: connecting to dozens of recruiting platforms with different APIs and auth methods, keeping token costs under control when the agent discovers and calls actions across ATS, CRM, and email systems, and preventing prompt injection from untrusted candidate data like resume fields and profile summaries.

Each ATS requires its own OAuth flow, pagination logic, and rate-limit handling — building and maintaining those connectors is a full engineering workload. An integration layer with agent-optimized actions lets the agent call one interface while the layer handles provider-specific complexity behind the scenes.

Every recruiting platform implements auth differently — OAuth flows, API keys, bearer tokens — and each requires separate refresh logic and credential management. When sourcing agents serve multiple customers on Greenhouse, Lever, or Bullhorn, the auth matrix grows fast. Infrastructure that handles auth across providers per tenant removes that burden.

Instead of pre-loading every action definition into the agent's context, use a search-first pattern where the agent queries an action catalog by natural language and loads only what it needs. Tool discovery cuts token usage significantly when sourcing at high volume across multiple providers.

Each ATS delivers events differently — some offer native webhooks, others require polling, and some use proprietary event buses. Building separate listeners per provider is ongoing work. Managed webhooks normalize event delivery across providers so the agent receives a consistent trigger regardless of the source ATS.

Sourcing agents ingest candidate profiles containing free-text fields — summaries, cover letters, work history — that could carry injected prompts. OWASP ranks prompt injection as the top LLM risk. Input scanning that detects malicious instructions before they reach the agent's context window is the primary defense.

Sourcing agents process names, emails, phone numbers, and employment history at scale. Without scoped permissions limiting which fields each agent can access, a single vulnerability could expose candidate data across all connected systems. Audit trails and minimal-access policies are essential for GDPR and hiring compliance.

Other Recruiting Use-Cases

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Job Posting Distribution

Use StackOne to connect your AI agent to your ATS and job boards to automate job posting distribution.

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Reference Check Automation

Use StackOne to connect your AI agent to your ATS, survey tools, and messaging systems to automate reference checks.

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Offer Letter Generation

Use StackOne to connect your AI agent to your ATS, HRIS, and document management tools to automate offer letter generation.

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Application Screening

Use StackOne to connect your AI agent to your ATS, document stores, and messaging tools to automate application screening and shortlisting.

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Interview Scheduling

Use StackOne to connect your AI agent to your ATS, calendar, and messaging tools to automate interview scheduling.

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